/*
 *  ----------------------------------------------------------------------------------------------------
 *  @copyright: Copyright (c) 2004, 2010 Xiamen XingYueYou Network Technology Co.,Ltd., All rights reserved.
 *  ----------------------------------------------------------------------------------------------------
 *  @package base64.js
 *  @todo: base64加密
 *  
 *  @author xiehuilong
 *  @date 2014-10-30 20:00
 *  @version 1.0
 *  
 *  修改时间 修改人 修改内容
 *  -------------------------------------------------------------------------------
 *  
 */

var base64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; 
var base64DecodeChars = new Array( 
		-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 
		-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 
		-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 
		52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, 
		-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 
		15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, 
		-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 
		41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1); 

function base64encode(str) { 
	var out, i, len; 
	var c1, c2, c3; 

	len = str.length; 
	i = 0; 
	out = ""; 
	while(i < len) { 
		c1 = str.charCodeAt(i++) & 0xff; 
		if(i == len) 
		{ 
			out += base64EncodeChars.charAt(c1 >> 2); 
			out += base64EncodeChars.charAt((c1 & 0x3) << 4); 
			out += "=="; 
			break; 
		} 
		c2 = str.charCodeAt(i++); 
		if(i == len) 
		{ 
			out += base64EncodeChars.charAt(c1 >> 2); 
			out += base64EncodeChars.charAt(((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4)); 
			out += base64EncodeChars.charAt((c2 & 0xF) << 2); 
			out += "="; 
			break; 
		} 
		c3 = str.charCodeAt(i++); 
		out += base64EncodeChars.charAt(c1 >> 2); 
		out += base64EncodeChars.charAt(((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4)); 
		out += base64EncodeChars.charAt(((c2 & 0xF) << 2) | ((c3 & 0xC0) >>6)); 
		out += base64EncodeChars.charAt(c3 & 0x3F); 
	} 
	return out; 
} 

function base64decode(str) { 
	var c1, c2, c3, c4; 
	var i, len, out; 

	len = str.length; 
	i = 0; 
	out = ""; 
	while(i < len) { 
		/* c1 */ 
		do { 
			c1 = base64DecodeChars[str.charCodeAt(i++) & 0xff]; 
		} while(i < len && c1 == -1); 
		if(c1 == -1) 
			break; 

		/* c2 */ 
		do { 
			c2 = base64DecodeChars[str.charCodeAt(i++) & 0xff]; 
		} while(i < len && c2 == -1); 
		if(c2 == -1) 
			break; 

		out += String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4)); 

		/* c3 */ 
		do { 
			c3 = str.charCodeAt(i++) & 0xff; 
			if(c3 == 61) 
				return out; 
			c3 = base64DecodeChars[c3]; 
		} while(i < len && c3 == -1); 
		if(c3 == -1) 
			break; 

		out += String.fromCharCode(((c2 & 0XF) << 4) | ((c3 & 0x3C) >> 2)); 

		/* c4 */ 
		do { 
			c4 = str.charCodeAt(i++) & 0xff; 
			if(c4 == 61) 
				return out; 
			c4 = base64DecodeChars[c4]; 
		} while(i < len && c4 == -1); 
		if(c4 == -1) 
			break; 
		out += String.fromCharCode(((c3 & 0x03) << 6) | c4); 
	} 
	return out; 
} 

function utf16to8(str) { 
	var out, i, len, c; 

	out = ""; 
	len = str.length; 
	for(i = 0; i < len; i++) { 
		c = str.charCodeAt(i); 
		if ((c >= 0x0001) && (c <= 0x007F)) { 
			out += str.charAt(i); 
		} else if (c > 0x07FF) { 
			out += String.fromCharCode(0xE0 | ((c >> 12) & 0x0F)); 
			out += String.fromCharCode(0x80 | ((c >> 6) & 0x3F)); 
			out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F)); 
		} else { 
			out += String.fromCharCode(0xC0 | ((c >> 6) & 0x1F)); 
			out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F)); 
		} 
	} 
	return out; 
} 

function utf8to16(str) { 
	var out, i, len, c; 
	var char2, char3; 

	out = ""; 
	len = str.length; 
	i = 0; 
	while(i < len) { 
		c = str.charCodeAt(i++); 
		switch(c >> 4) 
		{ 
		case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: 
			// 0xxxxxxx 
			out += str.charAt(i-1); 
			break; 
		case 12: case 13: 
			// 110x xxxx 10xx xxxx 
			char2 = str.charCodeAt(i++); 
			out += String.fromCharCode(((c & 0x1F) << 6) | (char2 & 0x3F)); 
			break; 
		case 14: 
			// 1110 xxxx 10xx xxxx 10xx xxxx 
			char2 = str.charCodeAt(i++); 
			char3 = str.charCodeAt(i++); 
			out += String.fromCharCode(((c & 0x0F) << 12) | 
					((char2 & 0x3F) << 6) | 
					((char3 & 0x3F) << 0)); 
			break; 
		} 
	} 

	return out; 
}


module.exports = {
					//加密
					"base64encode":base64encode,
					//解密
					"base64decode":base64decode,
					//utf16-8
					"utf16to8":utf16to8,
					//utf8-16
					"utf8to16":utf8to16,
					};